1. Field of the Invention:
This invention relates to aircraft fuel tank devices which lessen the catastrophic results of ruptured fuel tanks. In particular, this invention pertains to inflatable fuel tank buffers for lessening the hydrodynamic ram effects accompanying projectile penetration through a fuel tank into an engine inlet.
2. Description of the Prior Art:
There are numerous devices which seek to lessen the severity of damage caused by projectiles, such as bullets, puncturing fuel tanks. Such devices include U.S. Pat. No. 2,404,418 to Walker for a Noncombustible Fuel Tank which uses either rigid or inflated inner cushions to provide a collection space for fuel, U. S. Pat. No. 2,735,635 to J. D. Hoffman which uses an inner gas barrier to lessen the possibility of ignition of fuel exiting a rupture, and U. S. Pat. No. 3,966,147 to Wittko et al. for a Hammock Supported Fuel Tank which uses gravity to provide a separation distance between the upper surface of fuel and the aircraft structure. These devices all seek to lessen the severe dangers posed when bullets penetrate a fuel tank. These dangers include fire as a specific threat because of the incendiary trail of the bullet, and ingestion of fuel by the aircraft's engine.
A primary kill mechanism of ballistic threats to combat aircraft is raw fuel ingestion. Aircraft fuel tanks typically are placed near engine inlet ducts on fighter type aircraft. If a projectile passes through the fuel tank, the hydrodynamic ram effects in the liquid fuel can cause severe damage to the surrounding structure resulting in dumping of large quantities of raw fuel directly into the engine inlet.